This invention relates to a tool insert.
Abrasive compacts are polycrystalline masses of abrasive particles, generally ultra-hard abrasive particles, bonded into a hard coherent mass. Such compacts are generally bonded to a substrate, typically a cemented carbide substrate. Diamond abrasive compacts are also known as PCD and cubic boron nitride abrasive compacts are also known as PCBN.
U.S. Pat. No. 4,807,402 describes an article comprising a support mass such as a cemented carbide mass having layers of abrasive compact bonded to each of the upper and lower surfaces thereof.
EP 0 714 719 describes a tool insert comprising first and second layers of abrasive compact bonded to a central or intermediate layer of cemented carbide, ferrous metal or high melting point metal. The tool component is such that it provides a nose and flank of abrasive compact, the nose and flank providing cutting points and edges for the tool insert. Such tool inserts may be cut, for example, by electrodischarge machining from an article described in U.S. Pat. No. 4,807,402.
U.S. Pat. No. 5,676,496 describes a metal cutting insert comprising a carbide substrate, and at least one body of superhard abrasive material, such as PCD or PCBN, bonded to an edge surface of the substrate and extending from one side surface to the other side surface of the substrate. A plurality of superhard bodies may be disposed at respective corners of the substrate. Methods of making similar inserts are disclosed in U.S. Pat. No. 5,598,621 and U.S. Pat. No. 5,813,105.
A major drawback of the methods of making directly sintered, multicornered inserts described in the prior art is one of scale, with a small number of cutting tool inserts being produced during a single high pressure, high temperature cycle.